[sdiy] Soldering Transistors

[Rob]

from what I have found, its *very* difficult to overheat modern trannies. I
would say that you have an ESD prob with your iron or are wiring them wrong.
Wiring them wrong happens with a lot of ratshack stuff, because when you get
that trannie assortment not *all* of them seem to pin out the way they look
on the back of the blisterpack.

I test them first for CBE and what pin goes to what.

Base to Emitter - Lowest resistance

Base to Collector - Higher resistance

Depending on what type of trannie it is, the positive or negative lead goes
to base, then just touch the other lead to the other two legs to find out
what the resistance is.


Rob

----- Original Message -----
From: "harry" <harrybissell at prodigy.net>
To: <rob at sleep-dream-die.com>
Cc: <synth-diy at node12b53.a2000.nl>
Sent: Monday, February 12, 2001 8:46 PM
Subject: Re: [sdiy] Soldering Transistors


> Hi Rob...
>
> This is not usually that much of a problem these days. First would be your
> soldering iron.  If it is one of those big trigger action gun types
(Weller, Wen, etc)
> that might be your problem. The magnetic field that collapses whrn you
release the trigger
> can kill certain (fragile) transistors.
>
> If your iron is too small, you have to heat the joint for too long. That
can do more
> damage than a larger iron for much less time. I use a 40 watt. I would not
go as low
> as 25W unless I had a damn good reason to choose that size (maybe SMT)
>
> The classic fix is to get a tiny alligator clip (or a special aluminum
clip designed for
> the job) and clip it on the lead you are soldering between the transistor
body and the
> iron.
>
> Also be sure that you are not killing the trannies by miswiring...
>
> H^) harry
>
> rob wrote:
>
> > I have this problem where every time I solder a transistor I overheat it
and it stops working.  What is the correct procedure for preventing this.
> > Rob Rickner
> >
> > PS Thanx for the Stylophone Scematics everyone
>